1. Field of the Invention
The present invention relates to a sensor using a functional thin film, and particularly, to a high sensitive micro-cantilever sensor and fabricating method thereof for reducing a size of a system, and for realizing a sensor of high sensitivity.
2. Description of the Background Art
Recently, miniaturized sensors based on a micro electron machine system (MEMS) process which integrates electric and machinery components to be micro size have rapid response property, and high sensitivity, and are suitable for mass production.
MEMS structure applies semiconductor fine processing technology, in which processes such as deposition and etching are repeated, to make micro products mass produced, and is operated by using electrostatic force, that is, pulling force between electric charges, magnetic force, and driving force by heat expansion difference. In addition, the MEMS has micro size and the power consumption can be reduced greatly, and therefore, the importance of the MEMS structure is emphasized with a system on chip (SOC) technology.
Recently, researches for developing sensors based on a cantilever fabricated by the MEMS process for detecting physical phenomena or chemical reactions are being processed actively.
Most of the conventional cantilever sensors measure static deflection caused by the heat or mass changing, or the change of resonant frequency using light source such as laser. However, it is difficult to reduce the size of the conventional sensor using the light source since the light source should be constructed.
FIG. 1 is a view showing the conventional cantilever sensor using the light source.
As shown therein, according to the conventional cantilever sensor, when a driving portion 11 detects the static deflection caused by the heat of the detecting material 12 or by the change of mass, or the change of the resonant frequency, sensing signals detected by the driving portion 11 are focused and collected into a sensing position diode 14.
In the conventional sensor, the light source 13 such as laser for changing the signal generated in the driving portion into the light signal, or the sensing position diode 14 for collecting the lights should be included, and therefore, there is a limit to reduce the size of the sensing system.
Therefore, an object of the present invention is to provide a high sensitive micro cantilever sensor and a method for fabricating thereof by which a size of a system can be greatly reduced by sensing a signal electrically to make the system suitable for mass producing, and a rapid sensing responding speed by performing driving and sensing simultaneously.
Also, it can be applied as a high sensitive humidity sensor, a mercury detecting sensor, a high-sensitive gas sensor, and a bio sensor detecting live material of few pico gram (pg)xcx9cfew microgram (xcexcg).
Also, it has a large displacement and driving power by using a piezoelectric cell of bimorph form, and therefore, it can be applied for various devices using above properties such as light switch.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.